There is a need for a compact, lightweight and easily portable patient lifting device to assist caregivers in lifting prone patients from a lower position, e.g., the floor, to a relatively higher position, e.g., a bed, table, gurney, or vehicle, etc.; for use in the home, in institutional settings, and in the outside world. Transferring of disabled patients is a leading cause of injury in the health-care industry, with the nursing occupation having among the highest incidence of back injury, despite the prior art and the availability of commercial patient lifts. These lifts are under-utilized for a number of reasons, such as restricted space in many hospital wards and bathrooms, cumbersome operating requirements, the indignity involved in the mode of transport, the additional time required for performing the transfer, and the unavailability of the lift at both the patient's starting and destination locations. In addition, many patients are essentially home-bound due to the unavailability of a conveniently portable lift, reducing their quality of life unnecessarily. A device is required that is simple to set up and use, feels safe, secure and is not intimidating for the patient, and can be transported with the patient.
This problem is pervasive in the home health care industry as well, where spaces are not designed for safe patient transfers, and the caregiver is often alone and has no help during lifts. Since conventional lifts are available in less than ten percent of the homes visited by home health care professionals, a device that can be easily brought from home to home is also required. In addition, most prior art lifting devices do not provide for the reduction of hip and back deflection during lifting. This is a significant problem, since if a person's hip or back is already injured, such uncontrolled deflections could exacerbate the existing condition, or possibly cause additional injury.
While this field contains considerable prior art, these devices have proven inadequate. For example, U.S. Pat. No. 4,805,248, issued to Lunau is typical of ceiling-mounted patient lifts. While effective, these are limited to use in very well defined areas. U.S. Pat. No. 3,137,011, issued to Fischer is representative of a common type of mobile patient lift. A major disadvantage of this design is that the patients are essentially suspended from a hook. The resultant swaying motion during transfer is disconcerting to most patients. In addition, the patient is transported in a partially reclined position, increasing their sense of helplessness and indignity, particularly if used outside in public.
U.S. Pat. No. 3,914,808, issued to Woods teaches the use of a short flexible sling in a front-loading orientation, with a pivoting column. The base must be relatively wide in order to avoid tipping as the column is rotated, and there is no means for compactly transporting or storing the lift. Additionally, the use of a fixed length sling requires that the patient be sitting precisely on the center of the sling, to avoid tipping the patient as the column is raised. This increases the time and training required to use the lift.
Pneumatically inflatable, and hydraulically expandable lifting bags are also known. For example, DE-U-1,897,870 discloses an extendable or inflatable lifting device having a pressure release valve assembly. U.S. Pat. No. 3,695,582, issued to Clay discloses a lifting jack for motor vehicles which uses fluid pressure for operating power to raise the wheel of a vehicle. The jack relies upon a pair of stacked hollow flexible plastic bags that may be filled with a suitable fluid.
In U.S. Pat. No. 5,606,785, issued to Shelberg et al., an inflatable air mattress positioner is provided for use with a casket, coffin or alternative container. The assembly includes a partially pneumatic pillow with a chamber in which is disposed a plurality of air chambers, each one of which has a corresponding air tube and valve assembly. A cushion coacts with the air bladders to position the head, upper arm, chest and shoulder region of a cadaver so that the cadaver chin is disposed in an acceptable proper height in relation with the chest. The assembly includes an inflatable air mattress having a plurality of air chambers which are independently inflatable to position a cadaver at an appropriate height and angle in the casket. Additional separate independent air bladders are also provided to be disposed under the cadaver to aid in positioning the cadaver and tilt the cadaver along its longitudinal axis for mourner viewing as well as positioning the back, arms, head, neck or any other part of the cadaver that requires adjustment.
In the U.S. Pat. Nos. 4,688,760, 4,786,032, 4,993,736, 5,651,149, and 5,669,086, all issued to Garmen et al., a variety of lifting apparatus are provided that include a base, a platform disposed above the base, a thrust mechanism positioned between the platform and the base to lift the platform with respect to the base. Garmen et al. often choose a pneumatic thrust mechanism in the form of stacked bellows including a flexible wall composed of substantially inelastic material and having a vertically spaced horizontal stiffener. The bellows include an inlet to allow a gaseous material to inflate each bag for applying lifting forces to the platform. U.S. Pat. No. 6,199,827, issued to Rimington, et al., also discloses an extendable or inflatable lifting device
None of the foregoing patents adequately address the problem of insuring that a lift is available at both a patient's starting and final locations. Patient transfer mattresses are also well known in the art which include at least two flexible material sheets, that together define a plenum chamber, with at least one sheet being completely perforated with small pinholes over its surface area, and which open up directly to the interior of the plenum chamber. Such prior art mattresses are used by arranging the perforated sheet so that it faces an underlying fixed, generally planar support surface, such as a floor or table. When the mattress is charged with pressurized air, the escape of air under pressure through the pinholes acts initially to jack a load placed upon the mattress (i.e., to lift the load in increments) and thereby creates an air bearing of relatively small height between the underlying fixed, generally planar support surface and the perforated flexible sheet.
For example, in U.S. Pat. No. 4,517,690, issued to Wegener, an air pallet is disclosed that is formed from upper and lower thin flexible film sheets sealed at their edges to form a plenum chamber. Wegener's air pallet functions to move a load with minimal friction over an underlying generally planar fixed support surface. The bottom thin flexible material sheet is perforated by small diameter perforations such as pin holes.
In U.S. Pat. No. 4,417,639, issued to Wegener, a pair of relatively rigid planar members are arranged overlying each other, and are coupled about their edges by a flexible film band to form a jacking plenum chamber. The upper planar member functions as the load support, having a gas inlet hole adjacent one edge. Gas under pressure enters an end of the jacking plenum chamber and escapes through the outer end which allows for jacking of the load. Wegener's design is only capable of jacking the load, e.g., a patient lying on the mattress, several inches above the underlying support surface.
In U.S. Pat. Nos. 7,107,641 and 7,376,995, a double chambered transfer mattress is provided that is capable of partial deflation that includes a top inflatable mattress and a bottom inflatable mattress that are separated by a common wall from one another. A selectable inlet/outlet valve is arranged for airflow communication between an interior chamber of the bottom inflatable mattress and a source of pressurized air. A one-way valve is positioned through the common wall so as to provide selective air flow communication between the top inflatable mattress and the bottom inflatable mattress so that when the inlet/outlet valve is closed, and air continues to escape from perforations in the bottom inflatable mattress, the one-way valve is actuated so as to prevent deflation of the top inflatable mattress.
In U.S. Application Publication No. 2005/0132490, a pneumatic lift is provided that includes inflatable mattresses that are stacked one atop another, with select ones of the inflatable mattresses being arranged in internal air flow communication. Each of the inflatable mattresses includes a top panel having a width, a length, a peripheral edge, a bottom panel having the same width, length, and a peripheral edge, and a perimeter band extending between the top panel and the bottom panel. The peripheral edges of the top and bottom panels are sealingly fastened to one another to form the inflatable mattress. The peripheral band defines at least one through-hole for air flow communication with the interior of at least one other inflatable mattress. A plurality of baffle-panels are also provided each having a width and a length and being attached to an inner surface of the top panel and an inner surface of the bottom panel so as to be transversely oriented between the top panel and the bottom panel. In this way, the baffle-panels define a pair of longitudinally extending air flow passageways disposed between an edge of the baffle-panels and an interior surface of the perimeter band. At least one conduit is arranged in air flow communication between the at least one through-hole in adjacent inflatable mattresses. A source of pressurized air is arranged in airflow communication with one of the at least one through-holes so as to be in airflow communication with the interior of one of the inflatable mattresses.